A bar of solid circular cross section is loaded in tension by forces p. the bar has length l=16in and diameter 0.50in. the material is a magnessium alloy having modulus of elasticity E=6.4*10^6 psi. the allowable stress in tension is epsillon allow=17000psi and the elongation of the bar must not exceed 0.04 in. what is the allowable value of the forces p?